Unmarshal stringbuffer gives null object

Question

Hi,
I'm using jDeveloper 10.1.3. to develop a webservice that calls the Oracle Business Rules engine.
In order to do this, I take the carrental example from OTN as a starting point.
The supplied java file uses Unmarshalling to read xml from a file into an object like this:
******************************************************************************88
//* Unmarshall a file
JAXBContext jc = JAXBContext.newInstance("rent");
Unmarshaller um = jc.createUnmarshaller();
String fs = System.getProperty("file.separator");
String xmlpath = "C:\\Jdev10g\\jdev\\mywork\\Rules\\rent\\data" + fs + "carrental.xml" ;
Object root = um.unmarshal(new File(xmlpath));
This works fine.
I want to do the same but now with the xml in a stringbuffer i.o. a file, like this:
//Unmarshal a stringbuffer
JAXBContext jc = JAXBContext.newInstance("rent");
Unmarshaller um = jc.createUnmarshaller();
StringBuffer xmlStr = new StringBuffer(buf1);
Object root = um.unmarshal(new StreamSource (new StringReader(xmlStr.toString())));
In this case, the resulting Object root is null.
The String buf1 variable contains the same xmlstring as is found in the carrental.xml file :
<repository xmlns="http://rules.oracle.com/carrental"
xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance">
<driver>
<driver-license-number>d111</driver-license-number>
<name>Dave</name>
<age>50</age>
<vehicle-type>sports</vehicle-type>
<license-type>full</license-type>
<pre-convictions>0</pre-convictions>
<pre-accidents>1</pre-accidents>
<able-to-drive>true</able-to-drive>
</driver>
<driver>
<driver-license-number>d222</driver-license-number>
<name>Martien van den Akker</name>
<age>18</age>
<vehicle-type>truck</vehicle-type>
<license-type>full</license-type>
<pre-convictions>0</pre-convictions>
<pre-accidents>0</pre-accidents>
<able-to-drive>true</able-to-drive>
</driver>
<driver>
<driver-license-number>d222</driver-license-number>
<name>Rob de Haanr</name>
<age>39</age>
<vehicle-type>truck</vehicle-type>
<license-type>full</license-type>
<pre-convictions>0</pre-convictions>
<pre-accidents>1</pre-accidents>
<able-to-drive>true</able-to-drive>
</driver>
</repository>
I followed the examples from the Sun website:
http://java.sun.com/webservices/docs/1.6/api/javax/xml/bind/Unmarshaller.html
The complete java file is:
package carrental;
import java.io.File;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.List;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.Unmarshaller;
import javax.xml.transform.stream.StreamSource;
import oracle.rules.rl.RuleSession;
import oracle.rules.sdk.dictionary.RuleDictionary;
import oracle.rules.sdk.exception.RepositoryException;
import oracle.rules.sdk.repository.RepositoryContext;
import oracle.rules.sdk.repository.RepositoryManager;
import oracle.rules.sdk.repository.RepositoryType;
import oracle.rules.sdk.repository.RuleRepository;
public class TestXML
static public void main( String[] args )
String result;
     try
TestXML myObject = new TestXML();
result = myObject.testRule("rob");
catch( Throwable t )
t.printStackTrace();
public String testRule (String buf)
String buf1 =
"<?xml version=\"1.0\"?><repository xmlns=\"http://rules.oracle.com/carrental\"\n" +
" xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\">\n" +
" <driver>\n" +
" <driver-license-number>d111</driver-license-number>\n" +
" <name>Dave</name>\n" +
" <age>50</age>\n" +
" <vehicle-type>sports</vehicle-type>\n" +
" <license-type>full</license-type>\n" +
" <pre-convictions>0</pre-convictions>\n" +
" <pre-accidents>1</pre-accidents>\n" +
" <able-to-drive>true</able-to-drive>\n" +
" </driver>\n" +
"</repository>\n" ;
try
//Unmarshal a stringbuffer
JAXBContext jc = JAXBContext.newInstance("rent");
Unmarshaller um = jc.createUnmarshaller();
StringBuffer xmlStr = new StringBuffer(buf1);
System.out.println("buf = " + buf1);
Object root = um.unmarshal(new StreamSource (new StringReader(xmlStr.toString())));
//* Unmarshall a file
JAXBContext jc = JAXBContext.newInstance("rent");
Unmarshaller um = jc.createUnmarshaller();
String fs = System.getProperty("file.separator");
String xmlpath = "C:\\Jdev10g\\jdev\\mywork\\Rules\\rent\\data" + fs + "singlecarrental.xml" ;
Object root = um.unmarshal(new File(xmlpath));
//load dictionary
String repoPath = "C:\\Jdev10g\\jdev\\mywork\\Rules\\rent\\dict" + fs + "CarxmlRepository";
final String jarstoreKey = "oracle.rules.sdk.store.jar";
// file based repository
RepositoryType jarType = RepositoryManager.getRegisteredRepositoryType( jarstoreKey );
RuleRepository repo = RepositoryManager.createRuleRepositoryInstance( jarType );
//fill in init property values
RepositoryContext jarCtx = new RepositoryContext();
jarCtx.setProperty( oracle.rules.sdk.store.jar.Constants.I_PATH_BASE, repoPath );
//init the repository instance. If the init is successful,
//we shall get a useable repository instance
repo.init( jarCtx );
RuleDictionary dict = repo.loadDictionary( "RobFileXML", "INITIAL" );
//init a rule session
String rsname = "vehicleRent";
String dmrl = dict.dataModelRL();
String rsrl = dict.ruleSetRL( rsname );
RuleSession session = new RuleSession();
session.executeRuleset( dmrl );
session.executeRuleset( rsrl );
List argList = new ArrayList(3);
argList.add( "rent" );
argList.add( root );
argList.add( "//*" );
session.callFunctionWithArgumentList( "assertXPath", argList );
return ("Klaar, resultaat = " + session.callFunctionWithArgument( "run", rsname )).toString();
catch( Throwable t )
t.printStackTrace();
return t.getMessage() + " Buf1 = " + buf1;
public String version() {
return "1.0";
As stated above: if I unmarshal the file all goes well.
Any help would be greatly appreciated
Regards, Rob

Answer 1

Yes, you cannot do that work outside of a function. This is
because of the way mxml is generated into AS and compiled.
Declare the variable in instance scope as you have it, but do
the assignment in a function called by the Application initialize
or creationComplete event,
Tracy